A lack of P causes stunted growth and smaller leaves, leaves turn bluish green and blotches often appear. Stems, leaf stems and main veins turn reddish-purple starting on the leafs underside. Hope that helped ya.
ok looks like seedlings to me, it takes 2 to 4 weeks seedling plain water, 4 to 6 weeks veg water + nutes start low work up , 6 to 9 week flower water + nutes . you can burn the seedlings by adding nutes now. my 2 cents worth good luck